JavaScript release notes

See this changelog for JavaScript features implemented in Firefox 5 and later.

JavaScript versions

Deprecated (). The explicit versioning and opt-in of language features was Mozilla-specific and is in process of being removed. Firefox 4 was the last version which referred to an JavaScript version (1.8.5). With new ECMA standards, JavaScript language features are now often mentioned with their initial definition in ECMA-262 Editions such as Edition 6 (ES2015/ES6).

JavaScript was released as version 1.0 in March 1996 in Netscape Navigator 2.0 and Internet Explorer 2.0.